JOHN FLESHER AP Environmental Writer

TRAVERSE CITY, Mich. — The Michigan Department of Environmental Quality said Friday it had accepted Dow Chemical Co.'s plan for cleaning up properties contaminated with dioxin released from its chemical plan in Midland.

About 1,400 properties in the city, most residential but some vacant, are believed polluted from airborne emissions of dioxin over much of the 20th century. Dioxin is a group of toxic byproducts from industrial processes that the World Health Organization says may impair the human immune and nervous systems and damage organs such as the liver. The U.S. Environmental Protection Agency is evaluating the potential cancer risk.

The cancer-causing herbicides dubbed "Agent Orange" were sprayed by the B.C. government during the ‘60s and ‘70s, according to documents obtained by CTV News.

Records show tens of thousands of gallons of the toxic mixture were applied to clear brush near highways and along power lines in the late 1960s and early 1970s – and in some cases the substance was sprayed next to homes.

Dredging began on a small section of the Passaic River in Newark, N.J. this week, more than 200 years after the first industries dumped their waste there.

Under the watchful eye of federal environmental officials, a contractor's dredge is digging 12 feet deep into the muck under the water's surface in what will be a summer-long effort to remove tons of dioxin-laced sediment from New Jersey's most polluted river.

"Anytime they pull contaminated sediments out of the river, that's a good thing," said Capt. Bill Sheehan, riverkeeper of the nearby Hackensack River.

But Sheehan and others are concerned that the dredging finally underway is for only a small sliver of the river, immediately in front of the old Diamond Alkali plant where the dioxin was dumped.

It was used to make Agent Orange, the toxic defoliant of the Vietnam War that stripped away the jungle canopy.

World Focus correspondent Mark Litke and producer Ara Ayer travel to Vietnam to report on the long term impacts of Agent Orange/Dioxin on the Vietnamese land and people. This video report was part of their series on New Vietnam.